RxJava Homework by Diana

app/build.gradle

@@ -46,4 +46,5 @@ dependencies {
     implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.7.0'
     implementation "io.reactivex.rxjava2:rxjava:2.2.21"
     implementation 'io.reactivex.rxjava2:rxandroid:2.1.1'
+    implementation "com.squareup.retrofit2:adapter-rxjava2:2.7.1"
 }

app/src/main/java/otus/homework/reactivecats/CatsService.kt

@@ -1,10 +1,10 @@
 package otus.homework.reactivecats
 
-import retrofit2.Call
+import io.reactivex.Single
 import retrofit2.http.GET
 
 interface CatsService {
 
     @GET("random?animal_type=cat")
-    fun getCatFact(): Call<Fact>
+    fun getCatFact(): Single<Fact>
 }

app/src/main/java/otus/homework/reactivecats/CatsViewModel.kt

@@ -5,40 +5,61 @@ import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
-import retrofit2.Call
-import retrofit2.Callback
-import retrofit2.Response
+import io.reactivex.Flowable
+import io.reactivex.android.schedulers.AndroidSchedulers
+import io.reactivex.disposables.CompositeDisposable
+import io.reactivex.schedulers.Schedulers
+import retrofit2.HttpException
+import java.io.IOException
+import java.util.concurrent.TimeUnit
 
 class CatsViewModel(
-    catsService: CatsService,
-    localCatFactsGenerator: LocalCatFactsGenerator,
+    val catsService: CatsService,
+    val localCatFactsGenerator: LocalCatFactsGenerator,
     context: Context
 ) : ViewModel() {
 
+    private val disposables = CompositeDisposable()
+
     private val _catsLiveData = MutableLiveData<Result>()
     val catsLiveData: LiveData<Result> = _catsLiveData
 
     init {
-        catsService.getCatFact().enqueue(object : Callback<Fact> {
-            override fun onResponse(call: Call<Fact>, response: Response<Fact>) {
-                if (response.isSuccessful && response.body() != null) {
-                    _catsLiveData.value = Success(response.body()!!)
-                } else {
-                    _catsLiveData.value = Error(
-                        response.errorBody()?.string() ?: context.getString(
-                            R.string.default_error_text
+        disposables.add(
+            catsService.getCatFact()
+                .subscribeOn(Schedulers.io())
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribe({ data ->
+                    _catsLiveData.value = Success(data)
+                }, { throwable ->
+                    _catsLiveData.value = when (throwable) {
+                        is IOException -> ServerError
+                        is HttpException -> Error(
+                            throwable.response()?.errorBody()?.string() ?: context.getString(
+                                R.string.default_error_text
+                            )
                         )
-                    )
-                }
-            }
 
-            override fun onFailure(call: Call<Fact>, t: Throwable) {
-                _catsLiveData.value = ServerError
+                        else -> Error(context.getString(R.string.default_error_text))
+                    }
+
+                })
+        )
+    }
+
+    fun getFacts(): Flowable<Fact> {
+        return Flowable.interval(2, TimeUnit.SECONDS, Schedulers.io())
+            .flatMapSingle { _ ->
+                catsService.getCatFact()
+                    .onErrorResumeNext(localCatFactsGenerator.generateCatFact())
+                    .subscribeOn(Schedulers.io())
             }
-        })
     }
 
-    fun getFacts() {}
+    override fun onCleared() {
+        super.onCleared()
+        disposables.clear()
+    }
 }
 
 class CatsViewModelFactory(

app/src/main/java/otus/homework/reactivecats/DiContainer.kt

@@ -2,6 +2,7 @@ package otus.homework.reactivecats
 
 import android.content.Context
 import retrofit2.Retrofit
+import retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory
 import retrofit2.converter.gson.GsonConverterFactory
 
 class DiContainer {
@@ -10,6 +11,7 @@ class DiContainer {
         Retrofit.Builder()
             .baseUrl("https://cat-fact.herokuapp.com/facts/")
             .addConverterFactory(GsonConverterFactory.create())
+            .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
             .build()
     }
 

app/src/main/java/otus/homework/reactivecats/LocalCatFactsGenerator.kt

@@ -2,7 +2,10 @@ package otus.homework.reactivecats
 
 import android.content.Context
 import io.reactivex.Flowable
+import io.reactivex.Scheduler
 import io.reactivex.Single
+import io.reactivex.schedulers.Schedulers
+import java.util.concurrent.TimeUnit
 import kotlin.random.Random
 
 class LocalCatFactsGenerator(
@@ -15,7 +18,11 @@ class LocalCatFactsGenerator(
      * обернутую в подходящий стрим(Flowable/Single/Observable и т.п)
      */
     fun generateCatFact(): Single<Fact> {
-        return Single.never()
+        return Single.fromCallable {
+            val factsArray = context.resources.getStringArray(R.array.local_cat_facts)
+            val randomFact = factsArray.random()
+            Fact(randomFact)
+        }
     }
 
     /**
@@ -24,7 +31,11 @@ class LocalCatFactsGenerator(
      * Если вновь заэмиченный Fact совпадает с предыдущим - пропускаем элемент.
      */
     fun generateCatFactPeriodically(): Flowable<Fact> {
-        val success = Fact(context.resources.getStringArray(R.array.local_cat_facts)[Random.nextInt(5)])
-        return Flowable.empty()
+        val factsArray = context.resources.getStringArray(R.array.local_cat_facts)
+        return Flowable.interval(2, TimeUnit.SECONDS, Schedulers.io())
+            .map {
+                Fact(factsArray[Random.nextInt(factsArray.size)])
+            }
+            .distinctUntilChanged()
     }
 }